db.collection.count.txt

=====================
db.collection.count()
=====================

.. default-domain:: mongodb

.. contents:: On this page
   :local:
   :backlinks: none
   :depth: 1
   :class: singlecol

Definition
----------

.. method:: db.collection.count(query, options)

   .. note::

      MongoDB drivers compatible with the 4.0 features deprecate their
      respective cursor and collection ``count()`` APIs in favor of new
      APIs for ``countDocuments()`` and ``estimatedDocumentCount()``.
      For the specific API names for a given driver, see the driver
      documentation.

   Returns the count of documents that would match a
   :method:`~db.collection.find()` query for the collection or view. The
   :method:`db.collection.count()` method does not perform the
   :method:`~db.collection.find()` operation but instead counts and
   returns the number of results that match a query.

   .. important::

      - Avoid using the :method:`db.collection.count()` method without
        a query predicate since without the query predicate, the method
        returns results based on the collection's metadata, which may
        result in an approximate count. In particular,

        - On a sharded cluster, the resulting count will not correctly
          filter out :term:`orphaned documents <orphaned document>`.

        - :ref:`After an unclean shutdown
          <collection-count-accuracy-shutdown>`, the count may be
          incorrect.

      - For counts based on collection metadata, see also
        :ref:`collStats pipeline stage with the count <collstat-count>`
        option.


   .. list-table::
      :header-rows: 1
      :widths: 20 20 80
   
      * - Parameter
   
        - Type
   
        - Description
   
      * - ``query``
   
        - document
   
        - The query selection criteria.
          
          
   
      * - ``options``
   
        - document
   
        - Optional. Extra options for modifying the count.
          
          
   


   The ``options`` document contains the following fields:


   .. list-table::
      :header-rows: 1
      :widths: 20 20 80
   
      * - Field
   
        - Type
   
        - Description
   
      * - ``limit``
   
        - integer
   
        - Optional. The maximum number of documents to count.
          
          
   
      * - ``skip``
   
        - integer
   
        - Optional. The number of documents to skip before counting.
          
          
   
      * - ``hint``
   
        - string or document
   
        - Optional. An index name hint or specification for the query.
          
          .. versionadded:: 2.6
          
          
   
      * - ``maxTimeMS``
   
        - integer
   
        - Optional. The maximum amount of time to allow the query to run.
          
          
   
      * - ``readConcern``
   
        - string
   
        - Optional. Specifies the :term:`read concern`. The default level is
          :readconcern:`"local"`.
          
          .. include:: /includes/fact-enable-majority-readConcern.rst
          
          .. include:: /includes/usage-read-concern-majority.rst
          
          .. include:: /includes/fact-count-readConcern.rst
          
          .. versionadded:: 3.2
          
          
   


   :method:`~db.collection.count()` is equivalent to the
   ``db.collection.find(query).count()`` construct.

.. seealso:: 

   - :method:`cursor.count()`
   - :method:`db.collection.estimatedDocumentCount()`
   - :method:`db.collection.countDocuments()`

Behavior
--------

Count and Transactions
~~~~~~~~~~~~~~~~~~~~~~

You cannot use :dbcommand:`count` and shell helpers
:method:`~cursor.count()` and :method:`db.collection.count()` in
:ref:`transactions <transactions-ops-count>`.

For details, see :ref:`Transactions and Count Operations
<transactions-ops-count>`.

Sharded Clusters
~~~~~~~~~~~~~~~~

.. include:: /includes/extracts/fact-count-on-sharded-clusters-method-db.collection.count.rst

Index Use
~~~~~~~~~

.. include:: /includes/fact-count-index-use.rst

.. _collection-count-accuracy-shutdown:

Accuracy after Unexpected Shutdown
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. |cmd| replace:: :method:`~db.collection.count()`
.. |opt| replace:: count

.. include:: /includes/fact-unexpected-shutdown-accuracy.rst

.. note:: 
   This loss of accuracy only applies to :method:`~db.collection.count()`
   operations that do *not* include a query predicate.

Examples
--------

Count all Documents in a Collection
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

To count the number of all documents in the ``orders`` collection, use
the following operation:

.. code-block:: javascript

   db.orders.count()

This operation is equivalent to the following:

.. code-block:: javascript

   db.orders.find().count()

Count all Documents that Match a Query
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Count the number of the documents in the ``orders``
collection with the field ``ord_dt`` greater than ``new
Date('01/01/2012')``:

.. code-block:: javascript

   db.orders.count( { ord_dt: { $gt: new Date('01/01/2012') } } )

The query is equivalent to the following:

.. code-block:: javascript

   db.orders.find( { ord_dt: { $gt: new Date('01/01/2012') } } ).count()